Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:



import java.awt.*;
import java.io.*;
import java.math.BigInteger;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

public class Main {

    static Main.MyScanner sc = new Main.MyScanner();

    static PrintWriter out = new PrintWriter(System.out);
//    static PrintStream out = System.out;

    public static void main(String[] args) throws ParseException {

        int n = sc.nextInt(),m = sc.nextInt(),mat[][] = new int[n][m] ;

        for(int i = 0 ; i < n ; i++) for(int j = 0 ; j < m ; j++) mat[i][j] = sc.nextInt() ;

        int ans = 0 ;

        ArrayList<Integer> rows = new ArrayList<>(),col = new ArrayList<>() ;

        if(n <= m) {
            for(int i = 0 ; i < n ; i++) {
                int count = solveRow(mat,i) ;
                rows.add(i); rows.add(count) ;
                ans += count ;
            }
            for(int i = 0 ; i < m ; i++) {
                int count = solveCol(mat,i) ;
                col.add(i);col.add(count) ;
                ans += count ;
            }
        } else {
            for(int i = 0 ; i < m ; i++) {
                int count = solveCol(mat,i) ;
                col.add(i);col.add(count) ;
                ans += count ;
            }
            for(int i = 0 ; i < n ; i++) {
                int count = solveRow(mat,i) ;
                rows.add(i); rows.add(count) ;
                ans += count ;
            }
        }

        int sum = 0 ;

        for(int i = 0 ; i < n ; i++) for(int j = 0 ; j < m ; j++) sum += mat[i][j] ;

        if(sum == 0) {
            System.out.println(ans);
            for(int i = 0 ; i < rows.size() ; i += 2) {
                int rowNo = rows.get(i)+1,count = rows.get(i+1) ;
                while (count-->0) System.out.println("row " + rowNo);
            }
            for(int i = 0 ; i < col.size() ; i += 2) {
                int rowNo = col.get(i)+1,count = col.get(i+1) ;
                while (count-->0) System.out.println("col " + rowNo);
            }
        }
        else System.out.println(-1);

        out.close();
    }

    private static int solveCol(int[][] mat, int col) {
        int min = 1000 ;
        for(int i = 0 ; i < mat.length ; i++) min = Math.min(min,mat[i][col]) ;
        for(int i = 0 ; i < mat.length ; i++) mat[i][col] -= min ;
        return min ;
    }

    private static int solveRow(int[][] mat, int row) {
        int min = 1000 ;
        for(int i = 0 ; i < mat[row].length ; i++) min = Math.min(min,mat[row][i]) ;
        for(int i = 0 ; i < mat[row].length ; i++) mat[row][i] -= min ;
        return min ;
    }

    static private class MyScanner {

        static public class Fen {
            public static long read(long[] tree,int idx){
                int sum = 0;
                while (idx > 0){
                    sum += tree[idx];
                    idx -= (idx & -idx);
                }
                return sum;
            }

            public static void update(long[] tree,int idx ,long val){
                int MaxVal = tree.length - 1 ;
                while (idx <= MaxVal){
                    tree[idx] += val;
                    idx += (idx & -idx);
                }
            }

        }
        Fen fen = new Fen();


        private static int[] compress(int[] arr) {
            int temp[] = new int[arr.length] ;
            for(int i = 0 ; i < arr.length ; i++) temp[i] = arr[i] ;
            Arrays.sort(temp);
            HashMap<Integer,Integer> hm = new HashMap<>() ;
            int point = 1 ;
            for(Integer x : temp) {
                if(!hm.containsKey(x)) {
                    hm.put(x,point++) ;
                }
            }
            for(int i = 0 ; i < arr.length ; i++) arr[i] = hm.get(arr[i]) ;
            return arr;
        }

        BufferedReader br;

        StringTokenizer st;

        public MyScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public long mod(long x) {
            // TODO Auto-generated method stub
            return (x % 1000000007);
        }

        boolean hasNext() {
            if (st.hasMoreElements())
                return true;
            try {
                st = new StringTokenizer(br.readLine());
            } catch (IOException e) {
                e.printStackTrace();
            }
            return st.hasMoreTokens();
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

        public long nextLong() {
            return Long.parseLong(next());
        }
    }

}